Which physical findings are characteristic of cat scratch disease (CSD)?

Updated: Feb 16, 2021
  • Author: Robert A Schwartz, MD, MPH; Chief Editor: Michael Stuart Bronze, MD  more...
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Answer

In 1-3 weeks, the inoculum-site lesion evolves from a small, 2- to 5-mm reddish-brown macule or vesicle to a papule or pustule (see the images below). Often, it is mistaken for an insect bite. Lesions typically are nonpruritic and heal in days to months without scarring.

Papulopustular lesions of a primary inoculation si Papulopustular lesions of a primary inoculation site on the hand of a 16-year-old patient. These lesions had been present for approximately 3 weeks. A cat scratch antigen skin test was positive with 15-mm induration. No treatment was administered, and her condition resolved spontaneously in 2.5 months. Courtesy of Andrew Margileth, MD.
A crusted primary inoculation papule on the neck o A crusted primary inoculation papule on the neck of a 4-year-old child. Note the adjacent lymphadenitis. This patient had contact with cats and had multiple scratches. Courtesy of Andrew Margileth, MD.

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